VM Virtualbox External Disks Network

Hi Guys,

I think somebody my help

Using VM Virtualbox 4.1 working fine in Win7
I am trying to set a network using all OS installed from External Disk
so far installed from 1TB external Disk
1 Server Windows 2008 configured as AD DS + DNS + DHCP (working fine)
1 XP
1 Windows 7

My Question is

How can I make them work in the same network???
that from XP can join the Domain getting IP address automatically from the DHCP Server

Issue having
xp cannot reach the domain, the domain name doesn't exist when trying to join the domain

all I know Virtualbox provide for each OS installed an Adapter Network "NAT" (all of them have access to internet)

Thanks Guys

I quit using VirtualBox years ago because it was difficult to network. Try VMware Player, free that may be easier and provide more networking options.
Joe